In a receiver of a communication system, it is common to include an analog-to-digital converter (ADC) and a digital signal processor (DSP). At the output of the DSP, there exists a slicing (decision) mechanism where remote transmitted symbols are estimated. At the slicer output, the decision (estimated remote symbols) and an error are obtained. The error is typically obtained by subtracting the slicer output (i.e., a hard decision) from its input (i.e., a soft decision).
Each analog circuit at a front end of the receiver, specifically, but not only, the ADC, is allowed to add a limited amount of noise to the system. The ADC requirements usually include a metric known as the effective number of bits (ENOB), which describes the quality of the ADC.
Since it is common practice to define the required performance for each system component by itself, a designer of each system component may add tuning or calibration mechanisms to allow adjustments until requirements defined by the system designer are met. These mechanisms are traditionally built for each component separately. However, such mechanisms are costly, complex, and not suited for use during system operation.